Not until weeks after the World Health Organization declared Ebola an international emergency on Aug. 6 did doctors in Mumbai start preparing.

“Ebola? I heard about it one month back,” said Pramod Nagarkar, superintendent at the city’s Hinduhridyasamrat Balasaheb Thackeray Trauma Care Centre, which sent two doctors to attend a day-long crash course about the ABCs of the deadly virus. “They give training: what is Ebola, how it happens, what are the treatments, what are the precautions to be taken.”

The steep learning curve in the hospital that serves as Mumbai’s first line of defense underscores the risks in the developing world -- and especially India. Of the 10 densest megacities, five are in south Asia with a combined population that exceeds Germany’s. They face overburdened health-care facilities and thousands who have traveled to the virus’s African epicenter for work.

“If it reaches India, it poses challenges unlike any other in the world,” said Temmy Sunyoto, a medical coordinator for Doctors Without Borders in New Delhi. “In Mumbai or Delhi, it just takes one patient to reach a hospital and with the state of the public-health facilities, I’m sure it would be very difficult to contain.”

While there have been no confirmed cases in India -- or anywhere in Asia -- the death of Ebola-infected Thomas Eric Duncan in Texas, as well as confirmed infections in two health workers who treated him, have accelerated preparations in the region. The worst-ever outbreak of the epidemic has killed more than 4,400, with its core in Guinea, Sierra Leone and Liberia.

Rainforests, cities

Ebola first surfaced in 1976 in remote villages near rainforests in Sudan and the Democratic Republic of Congo, near the Ebola River. The current outbreak, the first in West Africa, has claimed more lives than all the others combined. It poses an unprecedented danger now because it has jumped to urban centers in Lagos, Madrid and Dallas.

The Bangladeshi government has medical teams at three airports, including at Dhaka, the world’s most densely populated city, and has trained doctors on how to handle Ebola cases, said Mahmudur Rahman, director of the Institute of Epidemiology, Disease Control and Research.

A 20-bed facility for Ebola patients has been set up at Kurmitola General Hospital, five kilometers from the Dhaka airport, he said.

‘No facility’

In Karachi, the world’s third-densest megacity, “there is no facility to control infection” in the public sector, said Zafar Aijaz, director of health services there. “No case or alert for Ebola has been received. When we get it, then we will plan for it.”

Indian passengers wearing protective suits after they arrived at Delhi airport this evening from Ebola-hit Liberia in New Delhi, India, on Aug. 26, 2014. Eighty eight Indian nationals, who have been brought back from Ebola-hit Liberia, were screened for the deadly virus after their arrival at the airports here and one was put in isolation.

In the coming weeks and months, more cases are expected to be exported to different countries, said Ben Cowling, associate professor of infectious disease epidemiology at the University of Hong Kong’s School of Public Health. China and India are at risk with so many travelers going back and forth between West Africa, Cowling said.

India had about 3,000 migrants in Liberia as of July, 1,400 in Sierra Leone at June, 500 in Guinea at July, and 25,000 in Nigeria at August, according to the latest data from the foreign ministry.

The government’s Integrated Disease Surveillance Programme is monitoring 1,128 passengers who have entered India, as of Oct. 12. So far, all suspected Ebola cases have tested negative, said B.V. Tandale, doctor of epidemiology at the National Institute of Virology in Pune where samples are sent for analysis.

Quarantine site

In Delhi, India’s capital and also the world’s seventh densest megacity, the Ebola action plan is unclear beyond identifying Ram Manohar Lohia Hospital, about 13 kilometers (8 miles) northeast of Indira Gandhi International Airport, as the government-designated quarantine site for suspected cases.

H.K. Kar, medical superintendent at Ram Manohar, said he was not authorized to speak about the topic. Anshu Prakash, joint secretary at the national health ministry, didn’t return four calls to his mobile phone.

There is no cure for Ebola. Current treatment involves replacing fluids and using antibiotics to fight opportunistic infections. Supply of the experimental drug ZMapp, which has shown promise in animal tests and was used for some health workers, is currently exhausted.

Droplet size

The virus spreads through direct contact with bodily fluids -- blood, saliva and urine -- of an infected person and by contact with contaminated objects such as soiled linen.

Still, “theoretically, wet and bigger droplets from a heavily infected individual, who has respiratory symptoms caused by other conditions or who vomits violently, could transmit the virus -- over a short distance -- to another nearby person,” the WHO said Oct. 6.

“We see that even in places that are well prepared there can be breaches and the disease can get missed,” Bruce Aylward, the WHO’s assistant director-general in charge of the Ebola response, told reporters in Geneva on Oct. 14.

The WHO met with disease control agencies to push for Ebola preparedness in the world’s megacities, he said. “The next big thing is asking them: have you done a simulation, have you done protocol testing to make sure these things really work, that’s where you usually find the gaps,” Aylward said.

Dense metropolis

The good news for greater Mumbai -- 18 million people crowded into slums and high rises that make up the world’s second-most densely populated megacity after Dhaka -- is that its main Ebola quarantine site is a one-year-old, relatively clean and empty trauma center close to the international airport.

The bad news is that it has no intensive care unit, blood bank or magnetic resonance imaging and computerized tomography scan machines. Nor does it provide its staff with respirator masks, which are recommended by the WHO and the U.S. Centers for Disease Control and Prevention.

“We should have them ideally, but they’re not here,” Nagarkar said.

Indian guidelines direct only lab technicians who might get exposed to fine aerosols to use the masks.

The Bal Thackeray center, alongside a highway about 5 kilometers north of Chhatrapati Shivaji International Airport, is where patients who land in Mumbai with Ebola symptoms are first taken.

Patients who exhibit signs of Ebola -- high fever, abdominal pain, bleeding -- and are entering from one of the affected countries in West Africa or after a layover at the international airport in Lagos, or have had recent contact with an Ebola patient -- are immediately moved by ambulance to Kasturba Hospital for Infectious Diseases.

Tested negative

There were three possible cases in the last month: an immigrant from Nigeria, a migrant worker from the north Indian state of Uttar Pradesh and a Mumbai native who also flew home from West Africa, Bal Thackeray’s Nagarkar said. All have tested negative for the virus, but are being monitored. The virus’s incubation period can extend to as long as 21 days.

At Bal Thackeray, patients are quarantined on the empty 10th floor, where blood samples are drawn and sent to the National Institute of Virology for analysis.

The next 24 hours, approximately the amount of time the lab takes to get back to Bal Thackeray by phone or e-mail with the test result, are critical. The patient, who would be kept in a 12-bed ward with only other suspected Ebola cases, is checked three times daily by doctors.

Doctors and nurses treating the patients at Bal Thackeray wear special protective kits that include impermeable gowns, caps and shoe covers; these must be disposed after each visit. Treating one suspected Ebola case requires 12 to 14 personal protection kits a day, each costing the hospital approximately 1,200 rupees ($19.64), Nagarkar said.

“It’s true that if it gets into the country and escapes one of the cities, it could be a real problem,” said Tandale of the National Institute of Virology. “Health care in smaller cities is not of the same quality. But the focus right now is keeping it out of the population by keeping it quarantined and isolated, if it enters the country.”